The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be embodiments of the invention.
In recent years, there has been explosive growth in the number of portable and handheld devices that include but are not limited to sensors such as accelerometers, gyros, magnetometers, altimeters, and/or pressure sensors. Examples of such devices include smart phones, cell phones, gaming devices, and wearable devices (or wearables).
In gaming devices, tilt or angles of rotation are often tracked and used to control elements of the game. A large number of wearables target health and fitness applications where steps taken and flights of stairs taken by device users are tracked utilizing accelerometers and altimeters.
Inertial navigation is a method utilizing accelerometers, gyroscopes or gyros, and a microprocessor contained on a moving object to continuously calculate device positions utilizing dead reckoning the position, orientation, and velocity of the object. Dead reckoning is the process of calculating the current position by using a previously determined position and advancing that position based on estimated speeds over known elapsed time. A system implementing inertial navigation is self-contained and requires no external references. Inertial navigation has generally been used by aircraft, spacecraft, guided missiles, and ocean craft. Inertial navigation may be used in embodiments of the inventive concepts described in this disclosure targeting systems and devices for the wearables market.
Most health and fitness wearables on the market today may track one or more of the following: steps taken, number of stairs taken, heart rate, movement activity, and sleep patterns. These devices generally utilize accelerometers, altimeters, light sources and sensors, and voltage sensors to sense and detect the parameters they measure and track. Generally, these wearables do not require the combination of position and orientation tracking that may require algorithms utilized in inertial navigation.